Sharepoint 2010 IE9 401 Error, while other browsers work

Question

I have a problem on the following system:

A domain Sharepoint Foundation 2010 server named srv-sharepoint

Any client machine on the same domain.

When I try to connect to http://srv-sharepoint in IE I make a request and get a response (fiddler):

HTTP/1.1 401 Unauthorized
Server: Microsoft-IIS/7.5
SPRequestGuid: 350732e3-82e9-41ef-9c28-178eaaf504bb
WWW-Authenticate: Negotiate
WWW-Authenticate: NTLM
X-Powered-By: ASP.NET
MicrosoftSharePointTeamServices: 14.0.0.4762
Date: Fri, 03 Feb 2012 12:05:14 GMT
Content-Length: 0
Proxy-Support: Session-Based-Authentication

When I connect using firefox, under the Web Developer Console there are 2 Get requests that receive a 401 Unauthorized And a subsequent Get request that gets a 302 Redirect to Home.aspx that works

IE's behaviour is not consistent; there are times that sharepoint authentification works on IE. Most of MS products (word, excel, onenote, sharepoint workspace) are not working also when connecting to sharepoint items.

Looking at raw request the major difference between IE and Firefox is that firefox contains the Request Header Authorization

Thank you

Answer 1

I did not experience the problem after modifying the server hosts configuration and adding the server name to point to localhost.

Not pointing your SharePoint servers at themselves seems to be one of the most common mistakes according to Todd O. Klindt.

Answer 2

One question and one idea: Are you using 32 or 64-bit version of IE? When you see this error message in both bit versions and IE only, check setting DisableLoopBackRequest in registry from this link http://support.microsoft.com/kb/896861 (or steps from Method #1 first)